A tiny hummingbird that breeds in eastern North America. It hovers while taking nectar from flowers and migrates to Central America in autumn.
Males have a green back and a red throat. Females lack the male’s red throat.
Autumn migration at one Gulf Coast stopover followed a chain pattern: birds from the south passed first, followed by birds from farther north. Researchers analyzed hydrogen isotopes in feathers of hatch-year Ruby-throated Hummingbirds captured in Alabama. Birds assigned to about 30–35°N mainly passed in September, while those from 40–50°N mainly passed in October.
The team also tested whether body size or fuel stores explained timing; those measurements did not account for the pattern. At Fort Morgan, researchers sampled young birds during autumns in 2010, 2011 and 2014. Feather chemistry provided clues to natal latitude as the birds moved through the Gulf Coast stopover.
An extinction-risk assessment has not been added yet.
At Fort Morgan, natal latitude estimates were associated with passage timing: birds from the southeast mainly passed in September and northern birds in October. Repeated surveys at Gulf Coast stopovers can track when different groups move through.